• Ganna PortyankinaEmail author
Living reference work entry


A spider is a topographical feature of several dendritic troughs radially converging to a common central depression exclusively found in the southern polar areas of Mars.



Its troughs are irregular, radiating away from the center and merge, branch, and anastomose in a seemingly random pattern. Spiders were found either isolated or in groups of sometimes overlapping individuals. During ice-free summer, spiders show no albedo difference to the surrounding substrate: they are solely topographical features. Early in local spring however their albedo often contrasts with the surroundings: either spider’s bluish-bright (standard processed HiRISE false colors) troughs stand out against red substrate or dark troughs against bright substrate. Spiders should not be confused with dark fan deposits that appear in spring in the same area (Fig. 1) ( Seasonal Polar Fan-Shaped...


Central Depression Polar Area Central Bulge Wide Trough Sinuous Channel 
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© Springer Science+Business Media New York 2014

Authors and Affiliations

  1. 1.Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderUSA